package com.tedu.coolshark.filter;

import com.tedu.coolshark.entity.User;

import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebFilter(filterName = "MyFilter",urlPatterns = {"/insertProduct.html","/admin.html"})
public class MyFilter implements Filter {
    //初始化时执行
    public void init(FilterConfig config) throws ServletException {
    }
    //当过滤器销毁时执行的方法
    public void destroy() {
    }

    @Override
    //当接受到请求时会执行此方法,需要在此方法中进行判断,是否允许访问Controller成静态资源文件
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        //将父类类型转换成子类类型
        HttpServletRequest st=(HttpServletRequest) request;
        HttpServletResponse se=(HttpServletResponse) response;
        //得到会话对象
        HttpSession session=st.getSession();
        //从会话对象中的到登录成功时保存的用户信息
        User user=(User) session.getAttribute("user");
        if (user!=null){//登录过了
            chain.doFilter(request,response);
        }else{//代表未登录
            se.sendRedirect("/login.html");//重定向 让客户端重新向指定地址发出请求
        }
        System.out.println("过滤器执行了");
        chain.doFilter(request, response);//放行  允许访问

    }
}
